Conventional measuring instruments are available that measure one or more physical quantities of a measurement target and display these measured physical quantities as measurement values on a display part. Measuring instruments are often installed directly on or in the vicinity of the object to be measured.
Examples of such measuring instruments include field-installed apparatus such as pressure gauges, flow meters, and thermometers installed in factories. Other examples include water meters attached to water piping and gas meters attached to gas piping. Depending on the installation site environment, a worker needing to check the measuring instrument display may have to work in a constricted space, which might make it difficult for him or her to read the measurement value as displayed. For example, there may be cases in which the measurement value must be read upside down because its display direction on the display part is fixed in this direction.
Accordingly, an LCD display apparatus for a measuring instrument has been proposed, as described in Japanese Unexamined Patent Application Publication No. 2007-101825 (hereinafter “Patent Document 1”), which is hereby incorporate by reference herein in its entirety, having a display part that is devised so that its display can be easily checked. The display part of this measuring instrument LCD display apparatus is a dot matrix type liquid crystal display (LCD) part, and the display direction of a character string displayed on the liquid crystal display part can be changed by 90° each time a pushbutton switch is pressed. Thus, and as shown for example in FIG. 15, an operator can change the display direction of the character string on the liquid crystal display part in one of four ways (0°, 90°, 180°, 270°) and thereby select a display direction that is easy for him or her to read.
Nevertheless, a dot matrix type LCD consumes a large amount of power. Moreover, if a dot matrix type LCD is used in a battery operated type measuring instrument (e.g., a water meter or a gas meter), then battery life decreases, which increases the frequency of battery replacement.